Added support for Digitech QM1576 serial protocol parser The protocol

Makefile.am

@@ -176,6 +176,7 @@ endif
 # Hardware (DMM chip parsers)
 libsigrok_la_SOURCES += \
 	src/dmm/asycii.c \
+	src/dmm/qm1578.c \
 	src/dmm/bm25x.c \
 	src/dmm/bm52x.c \
 	src/dmm/bm85x.c \

src/dmm/qm1578.c

@@ -0,0 +1,210 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2014 Janne Huttunen <[email protected]>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @file
+ *
+ * qm1578.c
+ *
+ * Digitech QM1576 serial protocol parser for libsigrok.
+ * QM1576 is a 600 count RMS DMM, with Bluetooth 4.0 support.
+ * https://www.jaycar.com.au/true-rms-digital-multimeter-with-bluetooth-connectivity/p/QM1578
+ *
+ * The protocol is described at https://www.airspayce.com/mikem/QM1578/protocol.txt
+ *
+ * You can use this decoder with libsigrok and Digitech QM1578 via ESP32 Bluetooth-Serial converter
+ * available from the author at:
+ * https://www.airspayce.com/mikem/QM1578/QM1578BluetoothClient.ino
+ * which connects to the QM1578 over Bluetooth LE, fetches the 
+ * data stream and sends it on the serial port to the host, where this driver can read it
+ * with this command for example:
+ * sigrok-cli --driver digitech-qm1578:conn=/dev/ttyUSB1 --continuous
+ *
+ * See https://www.airspayce.com/mikem/QM1578//README for more data
+ *
+ * Author: [email protected]
+ */
+
+#include <config.h>
+#include <math.h>
+#include <libsigrok/libsigrok.h>
+#include "libsigrok-internal.h"
+
+#define LOG_PREFIX "digitech-qm1578"
+
+/* Number of digits the meter supports */
+#define MAX_DIGITS 4
+
+/* Decode the multiplier prefix from buf[11] */
+static int decode_prefix(const uint8_t *buf)
+{
+	switch (buf[11]) {
+	case 0x00: return 0;
+	case 0x01: return 3;
+	case 0x02: return 6;
+	case 0x03: return -9;
+	case 0x04: return -6;
+	case 0x05: return -3; /* For amps */
+	case 0x06: return -3; /* For volts */
+	default:
+		sr_dbg("Unknown multiplier: 0x%02x.", buf[11]);
+		return -1;
+	}
+}
+
+static float decode_value(const uint8_t *buf, int *exponent)
+{
+	float val = 0.0f;
+	int i, digit;
+
+	/* On overload, digits 4 to 1 are: 0x0b 0x0a 0x00 0x0b */
+	if (buf[8] == 0x0b)
+		return INFINITY;
+
+	/* Decode the 4 digits */
+	for (i = 0; i < MAX_DIGITS; i++) {
+		digit = buf[8 - i];
+		if (digit < 0 || digit > 9)
+			continue;
+		val = 10.0 * val + digit;
+	}
+
+	*exponent = -buf[9];
+	return val;
+}
+
+SR_PRIV gboolean sr_digitech_qm1578_packet_valid(const uint8_t *buf)
+{
+	/* 
+	 * First 4 digits on my meter are always 0d5 0xf0 0x00 0x0a
+	 * Dont know if thats the same for all meters or just mine, so ignore them
+	 * and just use the presence of the trailing record separator
+	 */
+	if (buf[14] != 0x0d)
+		return FALSE;
+
+	return TRUE;
+}
+
+SR_PRIV int sr_digitech_qm1578_parse(const uint8_t *buf, float *floatval,
+				     struct sr_datafeed_analog *analog, void *info)
+{
+	int exponent = 0;
+	float val;
+
+	(void)info;
+
+	/* serial-dmm will dump the contents of packet by using -l 4 */
+
+	/* Defaults */
+	analog->meaning->mq = SR_MQ_GAIN;
+	analog->meaning->unit = SR_UNIT_UNITLESS;
+	analog->meaning->mqflags = 0;
+
+	/* Decode sone flags */
+	if (buf[13] & 0x10)
+		analog->meaning->mqflags |= SR_MQFLAG_AUTORANGE;
+	if (buf[13] & 0x40)
+		analog->meaning->mqflags |= SR_MQFLAG_DC;
+	if (buf[13] & 0x80)
+		analog->meaning->mqflags |= SR_MQFLAG_AC;
+	if (buf[13] & 0x20)
+		analog->meaning->mqflags |= SR_MQFLAG_RELATIVE;
+	if (buf[12] & 0x40)
+		analog->meaning->mqflags |= SR_MQFLAG_HOLD;
+	if ((buf[13] & 0x0c) == 0x0c)
+		analog->meaning->mqflags |= SR_MQFLAG_MAX;
+	if ((buf[13] & 0x0c) == 0x08)
+		analog->meaning->mqflags |= SR_MQFLAG_MIN;
+	if ((buf[13] & 0x0c) == 0x0c)
+		analog->meaning->mqflags |= SR_MQFLAG_AVG;
+
+	/* Decode the meter setting. Caution: there may be others on other meters: hFE? */
+	if (buf[4] == 0x01) {
+		analog->meaning->mq = SR_MQ_VOLTAGE;
+		analog->meaning->unit = SR_UNIT_VOLT;
+		analog->meaning->mqflags |= SR_MQFLAG_AC | SR_MQFLAG_RMS;
+	}
+	if (buf[4] == 0x02) {
+		analog->meaning->mq = SR_MQ_VOLTAGE;
+		analog->meaning->unit = SR_UNIT_VOLT;
+		analog->meaning->mqflags |= SR_MQFLAG_DC;
+	}
+	/* what is 03 ? */
+	if (buf[4] == 0x04) {
+		analog->meaning->mq = SR_MQ_RESISTANCE;
+		analog->meaning->unit = SR_UNIT_OHM;
+	}
+	if (buf[4] == 0x05) {
+		analog->meaning->mq = SR_MQ_CAPACITANCE;
+		analog->meaning->unit = SR_UNIT_FARAD;
+	}
+	if (buf[4] == 0x06) {
+		analog->meaning->mq = SR_MQ_TEMPERATURE;
+		if (buf[10] == 0x08)
+			analog->meaning->unit = SR_UNIT_CELSIUS;
+		else
+			analog->meaning->unit = SR_UNIT_FAHRENHEIT;
+	}
+	if (buf[4] == 0x07 || buf[4] == 0x08 ||buf[4] == 0x09) {
+		analog->meaning->mq = SR_MQ_CURRENT;
+		analog->meaning->unit = SR_UNIT_AMPERE;
+		analog->meaning->mqflags |= SR_MQFLAG_DC;
+	}
+	/* 0x0a ? 0x0b? */
+	if (buf[4] == 0x0c || buf[4] == 0x0d || buf[4] == 0x0e) {
+		analog->meaning->mq = SR_MQ_CURRENT;
+		analog->meaning->unit = SR_UNIT_AMPERE;
+		analog->meaning->mqflags |= SR_MQFLAG_AC | SR_MQFLAG_RMS;
+	}
+	if (buf[4] == 0x0f) {
+		analog->meaning->mq = SR_MQ_VOLTAGE;
+		analog->meaning->unit = SR_UNIT_VOLT;
+		analog->meaning->mqflags |= SR_MQFLAG_DIODE;
+	}
+	if (buf[4] == 0x10) {
+		if (buf[10] == 0x04) {
+			analog->meaning->mq = SR_MQ_FREQUENCY;
+			analog->meaning->unit = SR_UNIT_HERTZ;
+		}
+		else {
+			analog->meaning->mq = SR_MQ_DUTY_CYCLE;
+			analog->meaning->unit = SR_UNIT_PERCENTAGE;
+		}
+	}
+	if (buf[4] == 0x20) {
+		analog->meaning->mq = SR_MQ_CONTINUITY;
+		analog->meaning->unit = SR_UNIT_OHM;
+	}
+
+
+	val = decode_value(buf, &exponent);
+	exponent += decode_prefix(buf);
+	val *= powf(10, exponent);
+
+	if (buf[12] & 0x80)
+		val = -val;
+
+	*floatval = val;
+	analog->encoding->digits = -exponent;
+	analog->spec->spec_digits = -exponent;
+
+	return SR_OK;
+
+}

src/hardware/serial-dmm/api.c

@@ -60,7 +60,6 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 	char ch_name[12];
 
 	dmm = (struct dmm_info *)di;
-
 	conn = dmm->conn;
 	serialcomm = dmm->serialcomm;
 	for (l = options; l; l = l->next) {
@@ -356,7 +355,16 @@ SR_REGISTER_DEV_DRIVER_LIST(serial_dmm_drivers,
 	 * Fold marks {{{ }}} with matching braces were added, to further
 	 * speed up navigation in the long list.
 	 */
-	/* asycii based meters {{{ */
+
+	DMM(
+		"digitech-qm1578", qm1578,
+		"Digitech", "QM1578", "115200/8n1",
+		DIGITECH_QM1578_PACKET_SIZE, 0, 0, NULL,
+		sr_digitech_qm1578_packet_valid, sr_digitech_qm1578_parse,
+		NULL
+	),
+
+        /* asycii based meters {{{ */
 	DMM(
 		"metrix-mx56c", asycii, "Metrix", "MX56C",
 		"2400/8n1", ASYCII_PACKET_SIZE, 0, 0, NULL,

src/libsigrok-internal.h

@@ -2472,6 +2472,16 @@ SR_PRIV gboolean sr_rs9lcd_packet_valid(const uint8_t *buf);
 SR_PRIV int sr_rs9lcd_parse(const uint8_t *buf, float *floatval,
 			    struct sr_datafeed_analog *analog, void *info);
 
+/*--- dmm/qm1578.c -----------------------------------------------------------*/
+
+#define DIGITECH_QM1578_PACKET_SIZE 15
+
+/* Dummy info struct. The parser does not use it. */
+struct qm1578_info { int dummy; };
+
+SR_PRIV gboolean sr_digitech_qm1578_packet_valid(const uint8_t *buf);
+SR_PRIV int sr_digitech_qm1578_parse(const uint8_t *buf, float *floatval,
+			     struct sr_datafeed_analog *analog, void *info);
 /*--- dmm/bm25x.c -----------------------------------------------------------*/
 
 #define BRYMEN_BM25X_PACKET_SIZE 15